Merge branch 'feature/example-cahn-hilliard' into 'master'

examples/CMakeLists.txt

examples/README.md

examples/cahn_hilliard/.doc_config

examples/cahn_hilliard/CMakeLists.txt

examples/cahn_hilliard/README.md

examples/cahn_hilliard/doc/_intro.md

examples/cahn_hilliard/doc/_main.md

examples/cahn_hilliard/doc/_model.md

examples/cahn_hilliard/doc/main.md

examples/cahn_hilliard/doc/model.md

examples/cahn_hilliard/img/animation.gif

examples/cahn_hilliard/main.cc

examples/cahn_hilliard/model.hh

examples/cahn_hilliard/params.input

examples/diffusion/doc/main.md

examples/diffusion/main.cc

test/references/example_cahn_hilliard-reference.vtu

...eferences/example_cahn_hilliard_parallel_p0-reference.vtu

...eferences/example_cahn_hilliard_parallel_p1-reference.vtu